It has become the practice in the manufacture of blown glass containers to, through evolutionary steps, increase the output of the IS machine from single gob to double gob, and most recently to triple gob operations with each section of the machine producing three blown containers in each cycle of the machine. The limitations in the past, with regard to the number of gobs which could be formed and delivered to an IS machine, has been generally dictated by availability of glass to a forehearth which extends from the melting furnace to a position overlying the glass forming machine. It should be understood that the forehearth brings the glass to a position adjacent the machine, where the glass may be fed through a feeder which will normally be at the extreme end of the forehearth. The feeder is elevated above the machine, and the streams of glass that issue from the feeder are severed into individual gobs, or mold charges, and delivered by gravity through chutes to the sections of the individual section glass forming machine positioned therebelow. As previously stated, the most recent forming machines have been of the type which will receive three gobs simultaneously and; therefore, it has been the practice to sever three gobs simultaneously for delivery to the individual sections of the IS machine being operated.
In a very recent development, disclosed in U.S. Application Ser. No. 166,224 filed July 7, 1980 in the name of Kirkman and Sherman, and assigned to the assignee of the instant application, there is shown a molten glass feeder of a unique configuration capable of delivering four or possibly more, gobs simultaneously from the feeder. Actually, the glass will be fed to the unique feeder orifice arrangement and the severing of the glass into gobs will occur beneath this feeder, or bowl, as is sometimes the term used in referring to the end of the forehearth, in which the glass accumulates and will be fed by means of gravity from the bottom thereof.
In this application there is shown a system by which four gobs, in line, are being simultaneously formed. The present invention is specifically directed to the mechanism for shearing these four gobs and is capable of shearing the gobs uniformly and simultaneously by the operation and action of a single driven cam. Obviously, it is necessary that the gobs arrive at the same section at precisely the same time. The machine will handle the glass and form the glass into parisons and move the glass from the parison molds to the blow molds and from the blow molds will be taken out of the machine. All of these operations which occur at each of the sections, occur in very limited time intervals. Thus, it is essential that not only the gobs arrive at the machine sections at essentially the same instance, but also that the gobs which are being severed be severed at the same instant in order to insure that they be of the same weight. One example of a typical, double gob, shear mechanism is illustrated in U.S. Pat. No. 2,681,530 issued June 22, 1941. The mechanism shown and described in this patent shows how the shear arms are mounted to be driven, as a pair, and shows details of what are termed "drop guides" that maintain the gobs in generally vertical altitude after severence. These guides are not shown in conjunction with the present invention, however their use would normally be present. They were omitted in the interest of simplification.
With the foregoing in view, it is an object of this invention to provide a mechanism for shearing four or more gobs of glass simultaneously from four or more streams of molten glass.